Low capacitance endoscope system

ABSTRACT

An endoscopic system for sensing one or more characteristics at an environment of a worksite comprises a shaft comprising a proximal end portion and a distal end portion; an electrically active sensor system comprising a sensor positioned to sense at least one characteristic of an environment in which the distal end portion of the shaft is located; an electrical power transmission line electrically coupled to the sensor and extending along the shaft, the electrical power transmission line configured to transmit power to the sensor; and a floating ground element electrically isolated from an earth ground and operably coupled to the electrically active sensor system. An overall capacitance between the electrical power transmission line and the floating ground element is greater than an overall capacitance between the floating ground element and earth ground.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 14/080,384,filed Nov. 14, 2013, which claims priority to U.S. ProvisionalApplication No. 61/726,879, filed Nov. 15, 2012 (now expired), which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure is generally directed to endoscopic systems. Moreparticularly, aspects of the present disclosure relate to endoscopicsystems that include electrically active components disposed at anapplied part of the system.

INTRODUCTION

Minimally invasive surgical techniques generally attempt to performsurgical procedures while minimizing damage to healthy tissue.Remotely-controlled instruments, which can includerobotically-controlled (teleoperated) or manually-controlledinstruments, can be used to perform various minimally invasiveprocedures remotely. In robotically-controlled (teleoperated) surgicalsystems, surgeons manipulate various input devices at a surgeon console(sometimes referred to herein as master inputs) to control one or morecorresponding remotely-controlled instruments at a remote site in apatient's body. The input at the surgeon console is communicated to apatient side cart that interfaces with one or more teleoperated surgicalinstruments, where teleoperated/telerobotic manipulation of the surgicalinstrument occurs to perform a surgical and/or other procedure on thepatient.

Minimally invasive surgical instruments may be used in a variety ofoperations and have various configurations. Many such instrumentsinclude a surgical end effector mounted at a distal end of a long shaftthat is configured to be inserted (e.g., laporoscopically orthoracoscopically) through an opening (e.g., body wall incision ornatural orifice) to reach a remote surgical site within a patient. Insome instruments, an articulating wrist mechanism is mounted to thedistal end of the instrument's shaft to support the end effector andalter an orientation (e.g., pitch and/or yaw) of the end effector withreference to the shaft's longitudinal axis. Teleoperated/teleroboticallycontrolled end effectors may be configured to perform various functions,including any of a variety of surgical procedures that areconventionally performed in either open or manual minimally invasivesurgical procedures.

The use of remotely-controlled, minimally invasive surgical instruments,whether teleoperated or manually-controlled, generally is aided by anendoscopic image capture system to capture real-time images from thesurgical site and provide the captured images to, for example, thesurgeon console or elsewhere for access by a user. In a teleoperatedsurgical system, such an endoscopic system also can be mounted at thepatient side cart. Such a system can include, among other elements, ashaft (either flexible or rigid), an image capture device at theproximal end of the endoscopic system, such as, for example, a camera, alight conductor (such as one or more fiber optics or a rod lens) thatcan provide images of the surgical site once the shaft is in positionproximate the surgical site to the image capture device at the proximalend, and a light source for illuminating the surgical site.

Portions of minimally invasive surgical instruments and/or tools thatmay contact the patient during their normal operation (sometimesreferred to as “applied parts”), and that are electrically active (e.g.,require electrical power to operate), can cause an electrical currentexceeding an allowable leakage current for the part to flow to earth orto a conductive part of the overall instrument, tool, or system that theinstrument or tool is a part of. Therefore, these parts may need to beisolated from, for example, one or more earth-grounded elements of theassociated surgical system in order to reduce the risk of electric shockto the patient. In particular, depending on the nature of the appliedpart and the type of contact the applied part may make with the patient,the applied part may fall into one of several classification ratings,for example, as set by the International Electrotechnical Commission(IEC) in the IEC 60601-1 safety standard. For example, an applied partthat may come in direct contact with a patient's heart may be requiredto meet at least the IEC 60601-1 Cardiac Float (“CF”) rating, while anapplied part that may come in direct contact with the patient, but notwith the patient's heart, may be required to meet at least the IEC60601-1 Body Float (“BF”) rating, which is less stringent than the CFrating. In light of various electrically active components employed in,for example, endoscopic image capture systems, such endoscopic systemsmay require their applied parts to be isolated from, for example,external/earth-grounded power supplies.

Further, the applied part of an endoscopic system may exchange outputand/or control signals with an electronic circuit, for example, at thepatient side cart, at the surgeon console, and/or at anelectronics/auxiliary control cart. In some cases, however, it may bedesirable to use an endoscopic system in the presence of electromagneticinterference (EMI) at the remote site in the patient. For example,electrocautery operations, in which tissue at a surgical site is subjectto application of cautery energy generated by the flow of electricalcurrent through an electrocautery instrument, require application of arelatively high amount of electrical current through a conductingelement in close proximity to other instruments at the remote site.

A need exists to provide endoscopic systems that use electrically activesensor systems to capture and provide information from a remote surgicalsite that are sufficiently electrically isolated in their applied parts.For example, it may be desirable to provide an endoscopic system thatmeets the requirements of a desired standard rating with regard toprotection from electrical shock, such as, for example, an IEC CFrating.

A need also exists to provide endoscopic systems that use electricallyactive sensor systems to capture and provide information from a remotesurgical site that are sufficiently shielded so as to result inacceptably low levels of noise interference occurring from EMI at theremote site.

It also may be desirable to provide an endoscopic system that canachieve both sufficiently low capacitance and current leakage (e.g., toachieve an IEC CF rating) and also is sufficiently shielded to result inacceptably low levels of EMI noise interference, for example, fromcautery procedures and/or other relatively high EMI generation at theremote site.

SUMMARY

The present disclosure solves one or more of the above-mentionedproblems and/or demonstrates one or more of the above-mentioneddesirable features. Other features and/or advantages may become apparentfrom the description that follows.

In accordance with at least one exemplary embodiment, the presentdisclosure contemplates an endoscopic system that can include anendoscope shaft having a proximal end and a distal end, and anelectrically active sensor system including at least one sensor mountedproximate the distal end and positioned to sense at least onecharacteristic of an environment in which the distal end is located. Thecapacitance of the sensor system relative to earth ground maintainscurrent leakage to a level that meets a cardiac float rating.

In accordance with at least another exemplary embodiment, the presentdisclosure contemplates a method for sensing information at a remotesurgical site via an endoscopic system. The method can include, at aremote surgical site, sensing a characteristic of the remote surgicalsite via a sensor disposed proximate a distal end of an endoscope shaft.During the sensing, power can be transmitted to the sensor via a powertransmission line from a ground-referenced power source, and datasignals can be transmitted to the sensor via a data signal transmissionline from a processing circuit at a proximate end of the endoscopicshaft. In response to electromagnetic interference proximate the remotesurgical site, the method further can include substantially equalizinginduced voltages level changes in the data signal transmission line andthe power transmission. The method can further include maintainingcurrent leakage from one or more applied parts of the endoscopic systemat a sufficiently low level to meet requirements of a cardiac floatrating.

Additional objects and advantages will be set forth in part in thedescription that follows, and in part will be obvious from thedescription, or may be learned by practice of the present disclosureand/or claims. At least some of these objects and advantages may berealized and attained by the elements and combinations particularlypointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as disclosed or claimed. Theclaims should be entitled to their full breadth of scope, includingequivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be understood from the following detaileddescription either alone or together with the accompanying drawings. Thedrawings are included to provide a further understanding of the presentdisclosure, and are incorporated in and constitute a part of thisspecification. The drawings, which are incorporated in and constitute apart of this specification, illustrate one or more embodiments of thepresent disclosure and, together with the description, serve to explaincertain principles and operation. In the drawings,

FIG. 1 is a diagrammatic view of an exemplary embodiment of a minimallyinvasive teleoperated surgical system in which the present disclosuremay be applied;

FIG. 2 is a diagrammatic perspective view of a portion of a patient sidemanipulator arm of a minimally invasive teleoperated surgical system inaccordance with at least one exemplary embodiment of the presentdisclosure;

FIG. 3 is a diagrammatic view of an exemplary embodiment of anendoscopic image capture instrument for use with an endoscopic imagingsystem in accordance with the present disclosure;

FIG. 4 schematically illustrates an endoscopic system according tovarious exemplary embodiments of the present disclosure;

FIG. 5 schematically illustrates an endoscopic system according tovarious exemplary embodiments of the present disclosure;

FIG. 6 schematically illustrates another endoscopic system according tovarious exemplary embodiments of the present disclosure; and

FIG. 7 schematically illustrates yet another endoscopic system accordingto various exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION

This description and the accompanying drawings illustrate exemplaryembodiments and should not be taken as limiting, with the claimsdefining the scope of the present disclosure, including equivalents.Various mechanical, compositional, structural, electrical, andoperational changes may be made without departing from the scope of thisdescription and the claims, including equivalents. In some instances,well-known structures and techniques have not been shown or described indetail so as not to obscure the disclosure. Like numbers in two or morefigures represent the same or similar elements. Furthermore, elementsand their associated aspects that are described in detail with referenceto one embodiment may, whenever practical, be included in otherembodiments in which they are not specifically shown or described. Forexample, if an element is described in detail with reference to oneembodiment and is not described with reference to a second embodiment,the element may nevertheless be claimed as included in the secondembodiment. Moreover, the depictions herein are for illustrativepurposes only and do not necessarily reflect the actual shape, size, ordimensions of the system or the electrosurgical instrument.

Further, this description's terminology is not intended to limit theinvention. For example, spatially relative terms—such as “beneath”,“below”, “lower”, “above”, “upper”, “proximal”, “distal”, and thelike—may be used to describe one element's or feature's relationship toanother element or feature as illustrated in the figures. Thesespatially relative terms are intended to encompass different positions(i.e., locations) and orientations (i.e., rotational placements) of adevice in use or operation in addition to the position and orientationshown in the figures. For example, if a device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be “above” or “over” the other elements or features.Thus, the exemplary term “below” can encompass both positions andorientations of above and below. A device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Likewise, descriptionsof movement along and around various axes include various special devicepositions and orientations. In addition, the singular forms “a”, “an”,and “the” are intended to include the plural forms as well, unless thecontext indicates otherwise. And, the terms “comprises”, “comprising”,“includes”, and the like specify the presence of stated features, steps,operations, elements, and/or components but do not preclude the presenceor addition of one or more other features, steps, operations, elements,components, and/or groups. Components described as coupled may beelectrically or mechanically directly coupled, or they may be indirectlycoupled via one or more intermediate components. Mathematical andgeometric terms are not necessarily intended to be used in accordancewith their strict definitions unless the context of the descriptionindicates otherwise, because a person having ordinary skill in the artwould understand that, for example, a substantially similar element thatfunctions in a substantially similar way could easily fall within thescope of a descriptive term even though the term also has a strictdefinition.

Although the exemplary embodiments and descriptions below focus mainlyon an endoscopic system including an endoscopic distally positionedimage sensor for capturing images of a remote surgical site, theprinciples of the present disclosure can be applied in other endoscopicsystems, such as, for example, that utilize one or more electricallyactive components at an applied part (e.g., in a distal portion of theendoscope shaft). For example, aside from having image sensor systems,endoscopic systems in accordance with the present disclosure can includeany of a variety of electrically active sensor systems for providing oneor more characteristics of a remote site. Examples of such endoscopicsensor systems can include, but are not limited to, ultrasonicendoscopic probe systems, pressure transducer systems (e.g., formeasuring arterial blood pressure), electromagnetic sensor systems(e.g., for positioning and/or steering), temperature sensor systems,etc. Moreover, those having ordinary skill in the art would understandthat the present teachings can be applied in non-surgical applicationswherein it may be desirable to utilize a remotely-navigable instrumentthat utilizes one or more electrically active components (e.g., sensors)to capture and provide information at a remote site, and that maybenefit from the isolation and/or EMI noise interference shieldingconfigurations described herein, such as industrial sensing applicationsand/or location sensing and tracking applications.

As used herein, a “sensor system” and variations thereof includes notonly the sensor mechanism itself (e.g., temperature probe, image capturedevice, transducer, etc.) but also the circuitry, wiring, and otherancillary structure, including both electrically active and electricallypassive components, that enable the sensor to sense, convert, andtransmit data and power from or to a surgical site to be used by anoperator of the device and/or stored remotely from the surgical site asthose of ordinary skill in the art are familiar with.

Some conventional teleoperated surgical systems include electricallypassive endoscopic systems in which no electrically active elements arepresent at the distal end of the endoscopic shaft of the endoscopicsystem. In such systems, light is transferred through the endoscopicshaft through passive elements such as, for example, one or more opticalfibers or a rod lens, and an electrically active image sensor/cameracaptures light/images from the passive elements at the proximal end ofthe endoscopic system. With such a lack of electrically active appliedparts, sufficiently low capacitance and leakage currents between theapplied part and patient tissue can be achieved via a relatively simplemechanical insulation barrier.

Other endoscopic systems may rely on an applied part at the distal endof the endoscopic shaft of the endoscopic system that includes anelectrically active element. The use of the electrically active elementand its system components may require the applied part to include somelevel of electrical isolation from earth ground (e.g., a low capacitanceof the applied part to earth ground) to achieve, for example, at least aBF rating. Although the electrically active element may be fully orpartially exposed to patient tissue, in exemplary embodiments theelectrically active element is configured and positioned relative to theapplied part such that its electrical isolation from earth ground isthat of the applied part. An electrically active element, and associatedsignal/power transmission lines along the endoscopic shaft (e.g., asensor system), may however be susceptible to EMI if used in thepresence of EMI-generating surgical instruments such as, for example, anelectrocautery surgical instrument. EMI levels may be exacerbated as theapplied part's capacitance to earth ground is lowered. This is becauseinterfering voltage imposed on the associated signal/power transmissionlines by such EMI may increase as the capacitance of the applied part toearth ground decreases. In other words, while interference with theassociated signal/power transmission lines can be reduced by providing alow-impedance (e.g., high capacitance) path between the applied partcontaining the electrically active element and earth ground, suchrelatively high capacitance may cause a relatively high leakage currentbetween the applied part and patient tissue, which may thereby preventthe endoscopic system from meeting requirements to achieve a desiredrating for protection against electrical shock (e.g., whether a BF or CFrating), and thus, from being used for certain surgical procedures.

Various exemplary embodiments of the present disclosure provideendoscopic systems having relatively low capacitance between anelectrically active element at an applied part and patient tissue. Inparticular, various exemplary embodiments include, for example, anoptical communication link between circuitry at the proximal end of theendoscopic system and the associated robotically-controlled surgicalsystem, in combination with other elements of the endoscopic system toisolate a floating circuit which includes the electrically activeelement from the ground reference of the patient tissue and to reducethe capacitance between the electrically active element and itsassociated signal transmission lines, circuitry, etc., and patienttissue.

Furthermore, various exemplary embodiments of the present disclosureprovide endoscopic systems that shield an electrically active elementand other components from EMI. In particular, various exemplaryembodiments include tight coupling of the induced voltage experienced bysignal and power transmission lines between the electrically activeelement and circuitry at the proximal end of the endoscopic system, ahigh capacitance between the signal/power transmission lines and thefloating ground of a floating circuit which includes the electricallyactive element and the circuitry at the proximal end of the endoscopicsystem, and a continuous shielding element for shielding the floatingcircuit.

Further still, various exemplary embodiments of the present disclosureprovide an endoscopic system having relatively low capacitance betweenan electrically active element at an applied part and earth ground andthat shield the electrically active element and other components fromEMI. Exemplary embodiments also provide endoscopic systems which mayachieve a CF rating while being capable of protecting against noiseinterference resulting from operating in the presence of other surgicalinstruments that may generate relatively high levels of EMI. Thus, byachieving a CF rating, various exemplary embodiments provide anendoscopic system that may be employed for a variety of procedures,including procedures in the cardiothoracic cavity and heart.

With reference to FIG. 1, a diagrammatic view of an exemplary embodimentof a minimally invasive teleoperated surgical system 100 in which thepresent disclosure may be applied is depicted, although those ofordinary skill in the art will recognize that the principles herein canbe applied in manual minimally invasive surgical systems as well.Teleoperated surgical system 100 includes a patient side cart 105, asurgeon console 110, and an electronics/auxiliary control cart 115. Itis noted that the system components in FIG. 1 are not shown in anyparticular positioning and can be arranged as desired, with patient sidecart 105 being disposed relative to the patient so as to affect surgeryon the patient. A non-limiting, exemplary embodiment of a teleoperatedsurgical system that shares the general master-slave robotic controlprinciples of operation as those contemplated herein is a da Vinci® Si(model no. IS3000) commercialized by Intuitive Surgical, Inc. ofSunnyvale, Calif., although those of ordinary skill in the art wouldunderstand that the present disclosure is not in any way limited to thatparticular system.

Surgical system 100 is used to perform minimally invasive remotesurgical procedures by interfacing with and controlling a variety ofsurgical instruments. The patient side cart 105 can include a patientside manipulator arm 120 for holding, positioning, and manipulating thevarious surgical instruments and/or associated tools. As shown in FIG.1, the arm 120 of patient side cart 105 is configured to interface withand control one or more remotely-controlled surgical instruments and/orendoscopes (a single general instrument/endoscope 125 being depicteddiagrammatically for simplicity in FIG. 1).

In operation, surgeon console 110 receives inputs from a surgeon byvarious input devices, including but not limited to, for example, one ormore master grip input mechanisms 130 and/or one or more foot pedals135. Through the input devices, such as, for example the grip inputmechanisms 130, the surgeon console 110 serves as a master controller bywhich one or more instruments mounted at the patient side cart 105 actas a slave to implement any desired motions of the surgicalinstrument(s) (e.g., including their end effectors), and accordinglyperform a desired surgical procedure. Other input commands also may beprovided at the surgeon side console 110 to control variousfunctionalities of instruments mounted at the patient side cart 105. Byway of non-limiting example, a foot pedal 135 may be depressed to send acautery command to deliver electrosurgical energy from anelectrosurgical instrument mounted at the patient side cart 105.However, robotic surgical system 100 is not limited to receiving inputsat the surgeon console 110, and inputs may be received at any devicewhich can be configured to realize a manipulation of the surgicalinstrument(s) at the patient side cart 105. For example, a surgicalinstrument at the patient side cart 105 may be manipulated by a user(e.g., a surgeon) at the patient side cart 105, through the surgeonconsole 110 in combination with other surgical instrument supportdevice, or entirely through another surgical support device, as a resultof inputs received from the user. In addition, input devices can have avariety of configurations other than gripping mechanisms or foot pedals.Such configurations can include, but are not limited to, for example,joysticks, kinetic sensors, switches, thumb/finger controls, etc.

Surgeon console 110 may further include an electronic data processingsystem, including a processor, which may be configured to receive andprocess inputs from the surgeon console 110, or from any other surgicalinstrument support device, and control the manipulation of one or moresurgical instruments at the patient side cart 105 based on such inputs.However, elements of such electronic data processing system may beprovided elsewhere within robotic surgical system 100.

Electronics/auxiliary control cart 115 receives and transmits variouscontrol signals to and from the patient side cart 105 and the surgeonconsole 110, and can transmit light and/or other processing signals (forexample, to and from an endoscopic system mounted at the patient sidecart 105). For example, image processing light and image capture commandsignals can be provided from the electronics/auxiliary control cart 115,for example, in response to master command inputs provided at thesurgeon console 110, for capturing and processing images via anendoscopic imaging system mounted at the patient side cart 105. Thecaptured images may be displayed at a display 140 at the surgeon console110 and/or on a display 145 associated with the electronics/auxiliarycontrol console 115. Other electronics to control functionality of thevarious surgical instruments, such as electrosurgical energy generationunits, for example, also may be located at the electronics/auxiliarycontrol cart 115. Those having ordinary skill in the art are generallyfamiliar with such electronics/auxiliary control carts ofremotely-controlled robotic surgical systems.

In various exemplary embodiments, a camera control mechanism may be usedto send signals to an endoscopic camera manipulator (“ECM”) embedded atthe arm 120, and to an endoscopic camera, to control various aspectsrelated to capturing and processing video of a surgical site, such asthe position/orientation of the camera with respect to the surgicalsite, zoom of the camera lens, focus of the camera lens, etc. Thosehaving ordinary skill in the art are generally familiar with the use ofsuch teleoperated/telerobotic surgical systems to provide input from asurgeon at a surgeon console to ultimately effect operation of asurgical instrument interfacing with a patient side cart.

FIG. 2 illustrates a side elevation view of a patient side manipulatorarm 220 with an illustrative endoscopic camera 205 and an additionalsurgical instrument 225 mounted thereto according to an exemplaryembodiment of the present disclosure. In the exemplary embodiment, thepatient side manipulator arm 220 includes a “set-up” portion (not shownin FIG. 2) (which generally is passive and not controlled by the surgeonconsole) and an actively controlled “manipulator” portion 221, 222. Theportion 222 supports individual manipulator/actuator assemblies 204, 224(for simplicity, only two manipulator assemblies are illustrated, oneassociated with the endoscopic camera (i.e., ECM) and one with thesurgical instrument). The manipulator portion 222 can include arotatable base that rotates all of the manipulator assemblies andmounted instruments together about an arbitrarily defined roll axis. Themanipulator assemblies 204, 224 engage with transmission housings 203,223 associated with the endoscope camera instrument 205 and the surgicalinstrument 225, respectively, to control movement of instruments 205,225. In exemplary embodiments, not shown in FIG. 2, the distal portionsof the instrument shafts have wrist mechanisms that can be articulated(e.g., in arbitrary pitch and/or yaw) and rolled in response toactuators the manipulator portions 204 that transmit various forcesthrough the transmission housings 203, 223. The distal portions of themounted instruments 205, 225 are received through an entry guidestructure 208 that may lead to a cannula 207 that is introduced into thepatient's body at a single incision site or “port.” Although notdepicted in FIG. 2, the distal end portions of the instruments can exitout of the distal end of the cannula 207 (or other access structure) toaccess the remote surgical site.

The directions “proximal” and “distal” are used herein to definerelative locations of elements of surgical instruments/devices, withdistal generally being in a direction further along a kinematic chain,which can include a surgical instrument or endoscope camera, or closestto the surgical work site in the intended operational use of theassociated instrument used for performing surgical procedures. FIG. 2indicates the proximal and distal directions. For a further descriptionof an exemplary patient side cart for mounting and motion control ofsurgical and endoscopic instruments that can be utilized with thepresent disclosure, reference is made to U.S. App. Pub. No. US2011/0282358 A1, published Nov. 17, 2011, which is incorporated byreference in its entirety herein. A camera manipulator portion accordingto an exemplary embodiment may include more or less elements than thosedescribed with reference to FIG. 2. For example, a camera arm accordingto the present disclosure may include more, less, or none of the motionactuators set forth in FIG. 2 without departing from the scope of thepresent disclosure. Further, as noted above, the present disclosure isnot limited to an endoscopic image capture sensor or camera, and anendoscopic system according to the present teachings may include at itsdistal end other electrically active components, such as a sensor formeasuring characteristics of the environment proximate to the sensor,without departing from the scope of the present disclosure. Furtherstill, the present disclosure is not limited to teleoperated surgicalsystems, and thus, an endoscope camera according to the presentdisclosure may not be attached to a camera arm as that shown in FIG. 2,but may be manually controlled.

In operation of a teleoperated surgical system as the ones describedabove, a surgical procedure may include making one or more incisions ina patient's body. Such incisions are sometimes referred to as “ports”, aterm which may also mean a piece of equipment that is used within suchan incision. In some surgical procedures, several instrument and/orcamera ports may be used to provide access to and imaging of a surgicalsite; however, in alternative embodiments, as described with referenceto FIG. 2 for example, a single port may be used to introduce thevarious surgical and endoscope instruments.

Referring now to FIG. 3, an exemplary embodiment of an endoscopic imagecapture instrument for use with an endoscopic imaging system inaccordance with the present disclosure is illustrated. The endoscopicimage capture instrument 305 includes an endoscope shaft 307, atransmission housing 323 at the proximal end of the shaft 307, and anarticulable wrist portion 309 at a distal portion of the shaft 307. Asthose having ordinary skill in the art are familiar with, the wristportion 309 can be articulated via force transmission members (notshown) that extend along the shaft 307 from links of the wrist portion309 to the transmission housing 323 where they are actuated (e.g., viamodifying a force in the members) via actuators. In various exemplaryembodiments, the actuators can be servo motors associated with themanipulation portion (e.g., ECM) of the arm of a patient side cart thatare operative in response to master input commands provided at a surgeonconsole of a teleoperated surgical system. In the exemplary embodimentshown, the wrist portion 309 can be configured as a joggle joint wriststructure, as described for example in U.S. App. Pub. No. US2011/0152879 A1, filed Jun. 23, 2011, which is incorporated by referenceherein, although those having ordinary skill in the art would appreciatethat a single articulated wrist component may be used or an endoscopicimage capture instrument may not include a wrist structure at all. Atthe distal end 311 of the shaft 307, an image capture device (not shown)can be mounted inside the shaft 307.

In an exemplary embodiment, the image capture device is an electronicimage sensor, such as for example a CMOS (complimentary metal-oxidesemiconductor) or CCD (charge-coupled device) image sensor. As will beexplained in further detail below, various signal processing and powertransmission lines (e.g., cables) 340 can extend from the image capturedevice at the distal end 311 and along the shaft lumen so as to exit theproximal end of the endoscopic image capture instrument 305. Those lines340 can be connected to a signal processor and a power supply, which maybe separate or combined, and is depicted schematically as a combinedmodule 350 in FIG. 3. In various exemplary embodiments, module 350 maybe located at, for example, an electronics/auxiliary control cart or apatient side cart, such as electronics/auxiliary control cart 115, orthe patient side cart 105, as respectively illustrated in FIG. 1,without departing from the scope of the present disclosure. The distalend 311, and thus image capture device, in the exemplary embodiment ofFIG. 3 can be positioned by remotely controlling (e.g., through inputcommands at the surgeon console in a teleoperated surgical system or viamanual actuation in a manual system) movement of the wrist portion 309.

As noted above, an electronic surgical instrument/device such as, forexample, an endoscopic image capture instrument, may have one or moreapplied parts that come into contact with the patient during theirnormal operation and if not properly isolated could cause a currentexceeding an allowable leakage current to flow to earth ground orthrough a conductive path of the surgical system. Accordingly, based onthe nature of the instrument/device, and the type of contact theinstrument/device may make with the patient, the surgical systemassociated with the control and operation of the instrument/device mustbe designed such that the instrument/device meets certain requirementsfor protecting against electrical shock of the patient (for example, CFrating or BF rating as per the IEC 60601-1 safety standard). As will beexplained in detail below, endoscopic image capture, and otherendoscopic instruments having electrically active components disposed atan applied part, according to exemplary embodiments of the presentdisclosure may be configured to meet or fall below electrical currentleakage levels associated with the nature of the instrument/device andthe type of contact the instrument/device may make with the patent.

Further as described above, during performance of a procedure at theremote surgical site, the endoscopic image capture instrument can beintroduced at the site along with other surgical instruments forperforming a variety of procedures. Often, the distal ends of theendoscopic image capture instrument and the surgical instrument(s) arein close proximity to permit viewing of the site while performing asurgical procedure. Some of the exemplary procedures performed mayrequire the corresponding distal end (e.g. end effector) to receiveelectric current, as in, for example, an electrocautery procedure. Thisflow of current may generate electromagnetic interference (EMI) that mayaffect the operation of other instruments/devices, including theendoscopic camera instrument. For example, the flow of current mayaffect the various signal and power transmission lines that make up partof the image capture sensor system of the endoscopic image captureinstrument, such as, for example, endoscopic image capture instrument305 illustrated in FIG. 3. Furthermore, if the flow of current variesrapidly, as in alternating current for example, the flow of current mayalso generate differential interference among the various lines, whichmay exacerbate the degradation of the transmission of signals, bothanalog and digital, along the signal transmission lines of theendoscopic camera instrument.

As will be explained in detail below, exemplary embodiments according topresent disclosure, therefore, provide a shielding configuration for anendoscopic image capture system or other endoscopic sensor system, thatcan protect against the negative effects of EMI generated by proximatesurgical instruments such as, for example, an electrocautery instrumentso as to reduce signal noise along the signal transmission lines.

Moreover, in various exemplary embodiments, endoscopic systems can meetdesired electrical shock protection rating requirements while alsoprotecting against the effects of EMI generated by proximate surgicalinstruments and/or other sources in the surrounding environment.Examples of potential EMI sources may include, but are not limited to,defibrillators and/or MRI imaging systems.

FIG. 4 illustrates an endoscopic system 400 including adistally-positioned and electronic sensor for capturing information at aremote site according to various exemplary embodiments of the presentdisclosure. Endoscopic system 400 includes a grounded enclosure 405 thatis coupled to an endoscope shaft 410, and an electronic sensor 415 atthe distal end of the shaft 410. In various exemplary embodiments of thepresent disclosure, grounded enclosure 405 may be embodied within anelement of the endoscopic system, such as module 350 or transmissionhousing 323 illustrated in FIG. 3, and/or may be integrated within oneor more elements of a teleoperated surgical system such as teleoperatedsurgical system 100 illustrated in FIG. 1. For example, groundedenclosure 405 may be located at an electronics/auxiliary control cart ora patient side cart, such as electronics/auxiliary control cart 115 orpatient side cart 105, as respectively illustrated in FIG. 1, withoutdeparting from the scope of the present disclosure.

Endoscopic system 400 further includes a communication interface 440 forcommunicating with external devices and/or systems such as, for example,processing and control components of a robotic surgical system, such assystem 100 illustrated in FIG. 1. Endoscopic system 400 further includesa power interface 445 for supplying power to internal circuits anddevices, including electronic sensor 415, within endoscopic system 400.In an exemplary embodiment, endoscopic system 400 may be an endoscopicimage capture system and can include, for example, endoscopic camerainstrument 305 illustrated in FIG. 3, for capturing images of a surgicalsite. In such an embodiment, electronic sensor 415 may be an electronicimage sensor, such as for example, a CMOS image sensor. In an exemplaryembodiment some or all of the elements of endoscopic system 400 may bemounted on a patient side manipulator arm, such as arm 120, 220illustrated in FIGS. 1 and 2, respectively, of a robotic surgical systemsuch as robotic surgical system 100 illustrated in FIG. 1.

In an exemplary embodiment of the present disclosure, at least a portionof endoscope shaft 410 may be inserted into a patient's body through,for example, one or more of an entry guide and a cannula, such as, forexample, entry guide 208 and cannula 207 illustrated in FIG. 2.Electronic sensor 415 at the distal end of the endoscope shaft 410 maybe embodied as an electronic image sensor, such as the image captureinstrument described with respect to FIG. 3, to capture images of asurgical site. The sensor 415 may be powered by power received throughpower interface 445 via power transmission lines (not shown) extendingalong the shaft 410 to the sensor 415. During operation, control signalscan be exchanged between a processor/controller, e.g., at the surgeonconsole 110, patient side cart 105 and/or the electronics/auxiliarycontrol cart 115, logically coupled to the endoscopic system and theelectronic sensor 415 through communication interface 440. Thisexchange, for example, can provide video and/or other captured images ofthe surgical site to the surgeon console or to control a function of thesensor device 415 such as, for example, zooming in/out of an electronicimage sensor and/or to permit processing signal transmissions betweenthe sensor 415 and video processing circuitry. In various exemplaryembodiments of the present disclosure, the electronic image sensor mayprovide digital signals/data to the processor/controller representingimages captured at the surgical site. However, the present disclosure isnot so limited, and in various exemplary embodiments the electronicimage sensor may provide analog signals to represent images captured atthe surgical site without departing from the scope of the presentdisclosure.

Various exemplary embodiments of the present disclosure are configuredsuch that a capacitance between applied parts of the endoscopic system400 and earth ground is minimized, and may be minimized enough that atleast some of the exemplary embodiments may achieve desired ratings forprotection against electrical shock, such as, for example an IEC CFrating, which corresponds to about 500 pF when operating from a nominal230 volts AC (with nominal encompassing 230 volts +\−10%), 60 Hz earthgrounded power supply.

Further, when an endoscopic system such as endoscopic system 400operates proximate to one or more surgical instruments that may generateEMI, operation of electronic sensor 415 and/or communication to and fromelectronic sensor 415 may be degraded by the generated EMI. For example,video signals transmitted from electronic sensor 415 that is an imagesensor (either analog or digital) may be distorted by signal levelchanges induced by the generated EMI in a video signal transmission line(not shown) along the endoscope shaft 410. As will be described indetail below, exemplary embodiments of the present disclosure include ashielding configuration that can protect against the negative effects(e.g., noise) of external EMI in the operation of endoscopic system 400.

Further still, exemplary embodiments of the present disclosure canfurther minimize distortion caused by signal level changes induced bythe generated EMI along a video signal transmission line (not shown)along the endoscope shaft by structuring the capacitance between theconductors along the endoscope (e.g., video signal transmission line,control signal transmission line, and power transmission line relativeto a corresponding ground reference) (not shown) to be significantlylarger than the capacitance between applied parts of the endoscopicsystem 400 and earth ground.

Endoscopic System with Low Capacitance

FIG. 5 illustrates an endoscopic image capture system 500 that isconfigured to have relatively low capacitance and hence exhibitingrelatively low leakage current according to various exemplaryembodiments of the present disclosure. Endoscopic system 500 includes agrounded enclosure 505 that is coupled to an endoscope shaft 510, and anelectronic image sensor 515 disposed at the distal end of the endoscopeshaft 510. In an exemplary embodiment, endoscopic image capture system500 can be mounted at a patient side manipulator arm, such as arm 120,220 illustrated in FIGS. 1 and 2, respectively, of a robotic surgicalsystem, such as robotic surgical system 100 illustrated in FIG. 1.Although FIG. 5 and the descriptions set forth below are directed to anendoscopic image capture system, the present disclosure is not solimited, and exemplary embodiments of the present disclosure may includeother systems, such as ultrasonic endoscopic probes, endoscopic systemsusing pressure transducers (e.g., for measuring arterial bloodpressure), endoscopic systems using electromagnetic sensors (e.g., forpositioning and/or steering), endoscopic systems using temperaturesensors, and/or endoscopic systems using chemical sensors (such as pHsensors), etc.

Endoscopic system 500 further includes power transmission line 520 forproviding electric power to electronic image sensor 515, andoutput/control data transmission line 521 for exchanging output/controland video processing signals between electronic image sensor 515 and,for example, a surgeon console such as surgeon console 110 and/orelectronics/auxiliary control cart 115 illustrated in FIG. 1 andlogically coupled to endoscopic system 500 through communicationinterface 540.

Although power transmission line 520 is illustrated as a single line,the present disclosure is not so limited, and an exemplary embodimentmay include one or more power transmission lines. For example, invarious exemplary embodiments, electric power may be provided toelectronic image sensor 515 through two power transmission lines whichcan include, for example, a relatively low voltage line (e.g., about 1.8V) for powering logic circuitry in the electronic image sensor 515; anda relatively high voltage line (e.g., about 3.6 V) for powering thedetection of analog pixels and amplifiers in the electronic image sensor515.

Furthermore, although output/control data transmission line 521 isillustrated as a single line, the present disclosure is not so limited,and an exemplary embodiment may include separate lines for output dataand control data, or multiple lines for each of output and control data.For example, in various exemplary embodiments, one line may be providedfor the exchange of control data, and one or more lines may be providedfor transmission of high-speed image data from the image sensor 515 to,for example, a surgeon console such as surgeon console 110 and/orelectronics/auxiliary control cart 115 illustrated in FIG. 1. In oneexemplary embodiment, output/control data transmission line 521 mayinclude a twisted pair copper line.

Endoscopic system 500 further includes a floating ground 525, whichsurrounds transmission lines 520 and 521, and is separated fromtransmission lines 520 and 521 by an electrically insulative material530. The material 530 may be selected based on desirable dielectric,flexibility, and strength properties. In an exemplary embodiment, theelectrically insulative material 530 can include Ethylenetetrafluoroethylene (ETFE). However, exemplary embodiments of thepresent disclosure are not so limited, and the insulating material 530may include a variety of electrically insulative materials. Othernonlimiting examples of suitable materials include silicone, polyvinylchloride (PVC), and expanded polytetrafluoroethylene (ePTFE), withoutdeparting from the scope of the present disclosure.

Endoscopic system 500 further includes a communication interface 540within grounded enclosure 505 for exchanging data with other elements ofa teleoperated surgical system such as, for example, theelectronics/auxiliary control cart 115 and surgeon console 110illustrated in FIG. 1. Endoscopic system 500 further includes a powersupply interface 545 within grounded enclosure 505 for providingexternal power from a power source (e.g., as in power source 350 in FIG.3) to endoscopic system 500. Both communication interface 540 and powerinterface 545 can carry signals/electric power that is earth-grounded.However, the present disclosure is not so limited and communicationinterface 540 and power interface 545 may be grounded based on anon-earth-ground reference that is different from the floating groundreference 525 within endoscopic system 500.

Endoscopic system 500 further includes a processing circuit 550 withingrounded enclosure 505 coupled to communication interface 540 forprocessing signals exchanged between communication interface 540 andelectronic image sensor 515. However, exemplary embodiments of thepresent disclosure are not so limited, and some or all processing ofsignals may occur at, for example, other elements of a teleoperatedsurgical system such as, for example, the electronics/auxiliary controlcart 115 and/or surgeon console 110 illustrated in FIG. 1.

Processing circuit 550 can include an optical transceiver circuit 552,as depicted in FIG. 5, for transforming electrical signals received atcommunication interface 540 into optical signals and vice versa.However, exemplary embodiments of the present disclosure are not solimited. For example, in various exemplary embodiments, the endoscopicsystem may exchange data with external elements, such as elements of anassociated teleoperated surgical system, via optical signals, in whichcase, optical transceiver circuit 552 may be obviated.

Endoscopic system 500 further includes an optical transceiver circuit560 and an isolated power supply 565. Optical transceiver circuit 560 iscoupled to output/control transmission line 521 to exchangeoutput/control electrical signals with electronic image sensor 515, andto optical transceiver circuit 552 of processing circuit 550 to exchangeoptical signals with optical transceiver circuit 552. The use of opticaltransceiver circuit 560 and an optical connection to provide signals toan associated teleoperated surgical system (either directly or throughoptical transceiver circuit 552 of processing circuit 550, which may beearth-grounded) isolates output/control transmission line 521 andelectronic image sensor 515 (which are float-grounded) fromearth-grounded elements. As will be explained in further detail below,this isolation may reduce leakage current from endoscope shaft 510and/or electronic image sensor 515 to, for example, earth ground whenthese elements make contact with a patient.

Isolated power transformer 565 is coupled to receive earth-groundedpower from power interface 545. Isolated power supply 565 is furthercoupled to power transmission line 520 and to floating ground 525.Isolated power transformer 565 transforms earth-grounded power receivedfrom power interface 545 into float-grounded power supplied to theelectronic image sensor 515. In this way, the power interface 545, incommunication with an external power source, is isolated from the powersupply line of the transmission line 520 and from floating ground 525.Although endoscopic system 500 is shown as including isolated powertransformer 565 supplied through power interface 545, the presentdisclosure is not so limited, and power may be supplied through abattery, either external or internal to endoscopic system 500, withoutdeparting from the scope of the present disclosure.

In an exemplary embodiment, as illustrated in FIG. 5, endoscopic system500 may further include a circuit enclosure 553 coupled to the floatingground to provide EMI/induced voltage protection to optical transceivercircuit 560 and isolated power transformer 565. Circuit enclosure 553may include, for example, a Faraday cage, which helps ensure thatcurrent generated by the EMI/induced voltage flows uniformly through theenclosure, minimizing or eliminating secondary interference in thecircuits within. Specifically, in a condition in which the capacitanceCbox_5 is relatively large when compared to the capacitances Ciso_5a andCiso_5b, interfering current is caused to flow through the box and notthrough the active circuitry.

In addition to the features set forth above, and other features thatwould be understood by a person having ordinary skill in the art,various exemplary embodiments of the present disclosure include elementsto achieve a relatively low capacitance between the electronicallyactive system components of the endoscopic system (e.g., electronicimage sensor 515, transmission lines 520 and 521, and associatedcircuitry) and patient tissue (which may be earth-ground referenced). Inan exemplary embodiment, the capacitance of the overall endoscopicsystem according to the present disclosure can be low enough to maintaincurrent leakage from applied parts at levels that meet the requirementsof at least a CF rating (which corresponds to about 500 pF, whenoperating from a nominal 230 Volts AC, 60 Hz earth grounded powersupply), for example, in accordance with the standard set forth in IEC60601-1. However, it should be understood by those having ordinary skillin the art that the present disclosure can be useful in achieving otherelectrical shock protection ratings for applied parts as desireddepending on a particular application.

For example, the amount of leakage current is a function of thecapacitance between the applied part and earth ground, illustrated asCtotal_5 in FIG. 5. In various exemplary embodiments of the presentdisclosure, as in endoscope system 500, Ctotal_5 is, in significantpart, the addition of Cstray_5 (stray capacitance of various elements ofendoscopic system 500 relative to earth ground), Cbox_5 (capacitancebetween circuit enclosure 553 and earth ground), and Ciso_5 (capacitancebetween circuits within circuit enclosure 553 and earth ground; Ciso_5afor optical transceiver circuit 560 and Ciso_5b for isolated powertransformer 565), as these capacitances are in parallel betweenelements/circuits of endoscopic camera 500 and earth ground. Thus, invarious exemplary embodiments of the present disclosure, Ctotal_5 iskept low, in part by the use of a floating ground 525 for variouscircuits within endoscopic system 500 (e.g., electronic image sensor 515and transmission lines 520 and 521), and by the isolation provided bythe configuration of circuit enclosure 553 (Cbox_5); the opticalconnection optical transceiver circuit 560 that keeps internal signaldata lines (float-grounded) isolated from external signal data lines(earth-grounded) (Ciso_5a); and the isolated power supply (Ciso_5b),which produces floating-ground power for the floating circuit.

In particular, with reference to FIG. 5, the capacitance between thefloating-ground circuit and earth-ground includes Cstray_5 (straycapacitance between the applied part and earth ground), Ciso_5(capacitance generated at interfaces between the floating circuit andthe output/control signal interface (Ciso_5a) and between the floatingcircuit and the power interface (Ciso5b)), and Cbox_5 (capacitancebetween circuit enclosure 553 and grounded enclosure 505). With respectto Ciso_5, various embodiments of the present disclosure maintain arelatively low Ciso_5 by, for example, having an optical datacommunication link between the floating circuit within circuit enclosure553 (transceiver circuit 560) and earth-ground signal transmissioncircuits (e.g., optical transceiver circuit 552) for exchangingoutput/control signals between electronic image sensor 515 and externalelements such as, for example, a surgeon console (illustrated as Ciso_5ain FIG. 5). Ciso_5 can also be kept low by, for example, using anisolated power supply/regulator (illustrated as Ciso_5b in FIG. 5). Withrespect to Cbox_5, it may be kept low by building circuit enclosure 553such that the capacitance between the circuit enclosure 553 and thegrounded enclosure is low in ways known to those having ordinary skillin the art.

Endoscopic Electronic Sensor System with EMI Protection

FIG. 6 illustrates an endoscopic system 600 according to variousexemplary embodiments of the present disclosure. Endoscopic system 600includes a grounded enclosure 605 that is coupled to an endoscope shaft610, and an electronic image sensor 615 disposed at the distal end ofthe endoscope shaft 610. In an exemplary embodiment, endoscopic imagecapture system 600 can be mounted at a patient side manipulator arm,such as arm 120, 220 illustrated in FIGS. 1 and 2, of a teleoperatedsurgical system, such as teleoperated surgical system 100 illustrated inFIG. 1. Although FIG. 6, and the descriptions set forth below, aredirected to an endoscopic image capture system, the present disclosureis not so limited, and exemplary embodiments of the present disclosuremay include other systems, such as ultrasonic endoscopic probes,endoscopic systems using pressure transducers (e.g., for measuringarterial blood pressure), endoscopic systems using electromagneticsensors (e.g., for positioning and/or steering), endoscopic systemsusing temperature sensors, endoscopic systems using chemical sensorsetc.

Endoscopic system 600 further includes power transmission line 620 andoutput/control data transmission line 621 along endoscope shaft 610 forproviding electric power to electronic image sensor 615 and forexchanging output/control and video processing signals betweenelectronic image sensor 615 and, for example, a surgeon console such assurgeon console 110 and/or electronics/auxiliary control cart 115illustrated in FIG. 1 and logically coupled to endoscopic system 600through communication interface 640. Although power transmission line620 is illustrated as a single line, the present disclosure is not solimited, and an exemplary embodiment may include one or more powertransmission lines. Furthermore, although output/control datatransmission line 621 is illustrated as a single line, the presentdisclosure is not so limited, and an exemplary embodiment may includeseparate lines for output data and control data, or multiple lines foreach of output and control data. Output/control data transmission line621 may include a twisted pair copper line.

Endoscopic system 600 further includes a floating ground 625, whichsurrounds transmission lines 620 and 621, and is separated fromtransmission lines 620 and 621 by an electrically insulative material630. The material 630 may be selected based on desirable dielectric,flexibility, and strength properties. In one exemplary embodiment, theelectrically insulative material 630 can include Ethylenetetrafluoroethylene (ETFE). However, exemplary embodiments of thepresent disclosure are not so limited. Other suitable nonlimitingexamples of electrically insulative materials can include silicone,polyvinyl chloride (PVC), and expanded polytetrafluoroethylene (ePTFE),without departing from the scope of the present disclosure.

Endoscopic system 600 further includes a communication interface 640within grounded enclosure 605 for exchanging data with other elements ofa teleoperated surgical system such as, for example, theelectronics/auxiliary control cart 115 and surgeon console 110illustrated in FIG. 1. Endoscopic system 600 further includes a powersupply interface 645 within grounded enclosure 605 for providingexternal power from a power source (e.g., as in power source 350 in FIG.3) to endoscopic system 600. Both communication interface 640 and powerinterface 645 are considered as carrying signals/electric power that isearth-grounded. However, the present disclosure is not so limited andcommunication interface 640 and power interface 645 may be groundedbased on a non-earth-ground reference that is different from thefloating ground reference 625 used within endoscopic system 600.

Endoscopic system 600 further includes a processing circuit 650 withingrounded enclosure 605 coupled to communication interface 640 forprocessing signals exchanged between communication interface 640 andelectronic image sensor 615. However, exemplary embodiments of thepresent disclosure are not so limited, and some or all processing ofsignals may occur in, for example, other elements of a teleoperatedsurgical system such as, for example, the electronics/auxiliary controlcart 115 and surgeon console 110 illustrated in FIG. 1.

In various exemplary embodiments, endoscopic system 600 further includesa Faraday cage 655 within grounded enclosure 605 that is electricallycoupled to floating ground 625 to shield enclosed elements from EMI(namely, transceiver circuit 660 and isolated power supply 665).Transceiver circuit 650 is coupled to output/control data transmissionline 621 to exchange output/control electrical signals with electronicimage sensor 615, and to optical transceiver circuit 652 of processingcircuit 650 to exchange optical signals with transceiver circuit 652.The use of transceiver circuit 660 and a connection between transceivercircuit 660 (which is enclosed in Faraday cage 655) and transceivercircuit 652 of processing circuit 650 (which is outside Faraday cage 655and may be earth-grounded) isolates transmission lines 620 and 621 andelectronic image sensor 615 (which are float-grounded) from processingcircuit 650 (which may be earth-grounded). It is noted, however, thatexemplary embodiments of the present disclosure are not so limited. Forexample, in various exemplary embodiments, the endoscopic system mayexchange data with external elements, such as elements of an associatedteleoperated surgical system, via optical signals, in which case,optical transceiver circuit 652 may be obviated while maintaining adesired isolation without departing from the scope of the presentdisclosure. As will be explained in further detail below, this isolationmay reduce the effect of EMI on output/control and video processing datasignals along data signal lines within transmission lines 620 and 621.

Isolated power transformer 665 within Faraday cage 655 is coupled toreceive earth-grounded power from power interface 645. Isolated powersupply 665 is further coupled to power transmission line 620 and tofloating ground 625. Isolated power transformer 665 transformsearth-grounded power received from power interface 645 intofloat-grounded power supplied to the electronic image sensor 615. Inthis way, the power interface 645, in communication with an externalpower source, is isolated from power transmission line 620 and fromfloating ground 625. Although endoscopic system 600 is shown asincluding isolated power transformer 665 supplied through powerinterface 645, the present disclosure is not so limited, and power maybe supplied through a battery, either external or internal to endoscopicsystem 600, without departing from the scope of the present disclosure.

As above with reference to the description of FIG. 5, the amount ofleakage current is a function of the capacitance between the appliedpart and earth ground, illustrated as Ctotal_6 in FIG. 6. Ctotal_6 is,in significant part, the addition of Cstray_6 (stray capacitance ofvarious elements of the endoscope relative to earth ground), Cbox_6(capacitance between Faraday cage 655 and earth ground), and Ciso_6(capacitance between circuits within Faraday cage 655 and earth ground(Ciso_6a for transceiver circuit 660 and Ciso_6b for isolated powertransformer 665)), as these capacitances are in parallel betweenelements/circuits of endoscopic camera 600 and earth ground. Thus, invarious exemplary embodiments of the present disclosure, Ctotal_6 isreduced, in part, by the use of a floating-ground 625 as the electricalreference of various circuits within endoscopic system 600 and asisolation of the float-ground circuits provided by the configuration ofthe power transformer 655 (Ciso_6b). In exemplary embodiments, thefloating ground 625 serves as the electrical reference for the sensorsystem that includes at least electronic image sensor 615, transmissionlines 620 and 621, and Faraday cage 655 (which includes transceivercircuit 660 and isolated power transformer 665)).

In the exemplary embodiment illustrated in FIG. 6, isolated powertransformer 665 provides a high capacitance (illustrated as Cpwr_6)relative to the capacitance between the floating circuit and earthground illustrated as Ctotal_6 (i.e.,Cpwr_6>>Ciso_6a+Ciso_6b+Cbox_6+Cstray_6). In an exemplary embodiment:Cpwr_6 is about 10 micro Farads (uF); Ciso_6a is about 10 pico Farads(pF); Ciso_6b is about 20 pF; Cbox_6 is about 100 pF; and Cstray_6 isabout 50 pF, which yields a Cpwr_6 to Ctotal_6 ratio of about 55,000.However, the present disclosure is not so limited, and in variousexemplary embodiments a Cpwr_6 to Ctotal_6 ratio may be higher than55,000, and as low as about 10,000 or lower, without departing from thescope of the present disclosure. As will be explained below, thiscapacitance ratio minimizes the effects of EMI at least onoutput/control data transmission line 621.

Various exemplary embodiments of the present disclosure such as, forexample, endoscopic system 600, include elements that may improveperformance of the endoscopic system in the presence of EMI entering theendoscopic system from external sources such as, for example, cautery orother EMI-generating instruments being operated in close proximity tothe endoscope shaft at the remote surgical site. In particular, variousexemplary embodiments include elements to help to ensure thatcomponents, data transmission lines, and/or power transmission lines,are equally affected by any voltage level changes that might be inducedby EMI.

For example, the above-referenced floating ground 625 is configured as acontinuous shield around transmission lines 620 and 621, electronicimage sensor 615, and faraday cage 655, and thus helps to ensure thatthe components it shields are approximately equally affected by anyvoltage level changes that might be induced by EMI. Furthermore, therelatively large ratio of Cpwr_6 to Ciso_6 (i.e.,Cpwr_6>>Ciso_6a+Ciso_6b) also helps ensure that all shielded componentsare at nearly the same voltage in the presence of EMI.

Further still, a tight electromagnetic coupling of the transmissionlines helps ensure that the voltage induced on the transmission lines isnearly equal. Ensuring that any voltage induced within components of theendoscopic system (e.g., electronic image sensor 615 and othercomponents of that sensor system) is induced nearly equally onto thetransmission lines particularly improves performance of the endoscopicsystem at least because interference introduced into the output/controlsignal data lines appear to optical transceiver circuit 660 ascommon-mode. Accordingly, signal level changes caused by EMI on thetransmission lines remain low relative to the output/control signals,and thus, transmission/reception problems that could be caused by EMIare reduced.

In addition, the configuration of elements in various exemplaryembodiments of the present disclosure, such as, for example, theconfiguration of endoscopic system 600 illustrated in FIG. 6, allows fora significant reduction (over conventional endoscopic systems) in theamount of current induced on floating ground 625 in the presence of highvoltage interference, such as that which may be induced byelectrocautery instruments operating in the proximity of the imagesensor. For example, the capacitance between the floating ground andearth ground may be controlled across the frequency range covered byinterfering signals. Specifically, in various exemplary embodiments ofthe present disclosure, Ctotal_6 is formed, in part, by the Faraday cage655. The Faraday cage 655 and the floating ground shield 625 may beconfigured to form a high-frequency capacitor such that the Cbox_6 andCstray_6 components of Ctotal_6 are well-controlled and free ofresonances across a broad range of frequencies.

Furthermore, keeping capacitances illustrated in FIG. 6 as Cstray_6,Cbox_6, Ciso_6a, and Ciso_6b relatively low minimizes the generation ofdifferential mode interference on output/control signals exchangedthrough transmission lines 620 and 621 through the mutual inductancecoupling in the transmission lines. Any remaining differential modeinterference may be obviated by using differential signaling to exchangeoutput/control and processing signals along transmission lines 620 and621, and/or by using a balanced/twisted pair of conductors forexchanging the output/control signals along endoscope shaft 610.

Thus, various exemplary embodiments of the present disclosure minimizeand/or obviate the effects of EMI as a whole and/or across a broad rangeof frequencies on output/control signals exchanged between an electroniccomponent, such as electronic image sensor 615 at the distal end ofendoscopic shaft 610 and circuitry for controlling the endoscopic systemand/or processing data associated with the endoscopic system.

Endoscopic System for Producing Low Leakage Current and EMI Protection

As noted above, various exemplary embodiments of the present disclosure,such as the exemplary embodiment illustrated in FIG. 5, may achieve anIEC 60601-1 safety standard CF rating (which, for operating from anominal 230 Volts AC, 60 Hz earth grounded power supply, corresponds toabout 500 pF). However, maintaining a low applied part-to-earth-groundcapacitance (illustrated as Ctotal_5 in FIG. 5) may make an endoscopicsystem with an electrically active element, such as an endoscopic imagesensor, vulnerable to EMI. In particular, EMI may induce voltage alongconventional transmission lines that may increase errors inoutput/control signals exchanged along an endoscopic shaft between anendoscopic image sensor and, for example, a surgeon console. To counterthe possible effects of EMI due to keeping a relatively low Ctotal_5, invarious exemplary embodiments of the present disclosure EMI-inducedvoltage can be minimized by combining features of the various exemplaryembodiments of the present disclosure which may achieve an IEC 60601-1safety standard CF rating, such as the exemplary embodiment illustratedin FIG. 5, with features of the various exemplary embodiments which mayimprove performance of the endoscopic system in the presence of EMI,such as the exemplary embodiment illustrated in FIG. 6.

FIG. 7 illustrates an exemplary embodiment according the presentdisclosure. For simplicity, FIG. 7 includes a plurality of elementsalready illustrated in, and described with reference to, FIG. 5 and FIG.6. Those elements are identified in FIG. 7 according to theiridentifiers in their corresponding Figures, and their correspondingdescription is omitted here for brevity. At least the following featuresof the exemplary embodiment illustrated in FIG. 7 may realize anendoscopic electronic sensor system with relatively low capacitance toearth ground (so as to achieve relatively low leakage current and meetrequirements for an electrical shock protection rating), while alsoproviding EMI protection.

With respect to isolated power supply 565, which transformsearth-grounded power received from power interface 545 into floatinggrounded power for electronic image sensor 515, and with respect toendoscopic image sensor 515, various exemplary embodiments of thepresent disclosure are configured such that Cpwr_6>>Ciso_5, and alsosuch that Cpwr_6>>Ciso_5+Cbox_5+Cstray_5. As explained above, this helpsensure that all shielded components, such as, for example, transmissionlines 520 and 521, experience nearly the same level of induced voltagewhen in the presence of EMI. Accordingly, signal/power level changescaused by EMI on, for example, transmission lines 520 and 521 remain lowrelative to the output/control signals, which reducestransmission/reception problems that could otherwise be caused by EMI.

Furthermore, in various exemplary embodiments of the present disclosure,transmission lines 520 and 521 can be tightly coupled by, for example,being embodied in a balanced, twisted pair set of conductors. This helpsensure that transmission lines 520 and 521 are at nearly the samevoltage in the presence of EMI which reduces transmission/receptionproblems that could otherwise be caused by EMI on transmission lines, asit helps a receiver better identify received signal data.

Further still, combining the tight coupling of the signal lines withdifferential signal transmission of output/control data signals,counters the effect of differential mode interference that may be causedby high voltage variations (dv/dt) proximal to the signal lines (suchas, for example, the high dv/dt of electrocautery instruments), andthus, may further minimize transmission/reception problemsconventionally caused by EMI on transmission lines.

Further still, the use of Faraday cage 655 to enclose opticaltransceiver circuit 560 and isolated power transformer 565 can providesome shielding of these components from the effects of EMI. In additionthe use of floating ground 525 as a continuous shield further helps toensure that the components it shields (e.g., transmission lines 520 and521, optical transceiver circuit 560, and isolated power transmission565) are approximately equally affected by any voltage level changesthat might be induced by EMI external to the endoscopic system.

Further still, the capacitance between the floating ground and earthground may be controlled across the frequency range covered byinterfering signals. Specifically, in various exemplary embodiments ofthe present disclosure, Ctotal_5 is formed, in part, by the Faraday cage655. The Faraday cage 655 and the floating ground shield 525 may beconfigured to form a high-frequency capacitor such that the Cbox_5 andCstray_5 components of Ctotal_5 are well-controlled and free ofresonances across a broad range of frequencies.

Therefore, various exemplary embodiments of the present disclosuremaintain a low capacitance from an endoscopic system's applied part toearth-ground. Furthermore, various exemplary embodiments of the presentdisclosure minimize the effects of voltages induced by EMI into, forexample, transmission lines along an associated endoscopic shaft.Further still, various exemplary embodiments of the present disclosuremaintain a low capacitance from an endoscopic system's applied part toearth-ground while minimizing the effects of voltages induced by EMI.

Although the exemplary embodiments and descriptions above focus mainlyon an endoscopic system including an endoscopic image capture system forperforming remotely-controlled surgical applications, a person havingordinary skill in the art would recognize that the present disclosure isnot limited, and the principles of the present disclosure could beapplied in other endoscopic systems, such as, for example, sensorsystems for capturing and providing one or more characteristics of asurgical site, without departing from the scope of the presentdisclosure. Moreover, with respect to the terminology “surgicalprocedure,” “surgical site,” and variations thereof, those havingordinary skill in the art will appreciate that the present teachingsalso apply to non-surgical procedures performed at remote sites, suchas, for example, various diagnostic and/or therapeutic procedures;therefore the term “surgical” should be construed broadly to encompassany procedure in which an instrument is inserted through the patient'sbody to a remote location within the body to perform a surgical,diagnostic, and/or therapeutic procedure.

Other embodiments of the invention will be apparent to those havingordinary skill in the art from consideration of the specification andpractice of the present disclosure and claims herein. It is intendedthat the specification and examples be considered as exemplary only,with a true scope and spirit of the invention being indicated by thefollowing claims.

1. An endoscopic system comprising: an electrically active sensor systemcomprising a sensor; an electrical power transmission line electricallycoupled to the sensor, the electrical power transmission line configuredto transmit power to the sensor; and a floating ground elementelectrically isolated from an earth ground and operably coupled to theelectrically active sensor system, wherein an overall capacitancebetween the electrical power transmission line and the floating groundelement is greater than an overall capacitance between the floatingground element and earth ground.
 2. The endoscopic system of claim 1,wherein the floating ground element is operably coupled to provide anelectrical reference for the electrically active sensor system.
 3. Theendoscopic system of claim 1, wherein the floating ground elementcomprises a conductive structure at least partially surrounding theelectrical power transmission line.
 4. The endoscopic system of claim 1,further comprising an electrically insulating material separating thefloating ground element from the electrical power transmission line. 5.The endoscopic system of claim 1, wherein the sensor is an electronicimage sensor.
 6. The system of claim 1, wherein a ratio of capacitancebetween the electrical power transmission line and earth ground andcapacitance between the floating ground element and earth ground is in arange of from 10,000 and 55,000.
 7. The endoscopic system of claim 1,wherein an overall capacitance of the sensor system relative to earthground maintains current leakage from one or more applied parts of theendoscopic system to a patient to a predetermined current leakagecriterion.
 8. An endoscopic system comprising: a shaft comprising aproximal end portion and a distal end portion; an electrically activesensor system comprising: a sensor positioned to sense a characteristicof an environment in which the distal end portion is located, atransceiver circuit, a data transmission line electrically coupled tothe sensor and extending along the shaft, the data transmission lineconfigured to transmit data between the sensor and a signal processorvia the transceiver circuit, and a power transmission line electricallycoupled to the sensor and extending along the shaft, the powertransmission line configured to transmit power to the sensor; a floatingground element electrically coupled to the electrically active sensorsystem; a power regulator electrically coupled to the power transmissionline and to the floating ground element, the power regulator configuredto convert ground-referenced power received from an earth groundreferenced power source into floating ground element referenced powerand to output the floating ground element referenced power through thepower transmission line; and a circuit enclosure at least partiallyenclosing the transceiver circuit and the power regulator, the circuitenclosure being electrically coupled with the floating ground element.9. The endoscopic system of claim 8, wherein the transceiver circuit andthe circuit enclosure comprise conductive material.
 10. The endoscopicsystem of claim 8, wherein the floating ground element at leastpartially surrounds the data transmission line and the powertransmission line.
 11. The endoscopic system of claim 8, wherein thefloating ground element is electrically coupled to provide an electricalreference for the electrically active sensor system.
 12. The endoscopicsystem of claim 8, further comprising an electrically insulativematerial separating the floating ground element from each of the datatransmission line and the power transmission line.
 13. The system ofclaim 8, wherein the power regulator is operably coupled to provideelectrical power to the electrically active sensor system.
 14. Thesystem of claim 8, wherein a capacitance of the sensor system relativeto earth ground is less than 500 pF.
 15. An endoscopic systemcomprising: a shaft comprising a proximal end portion and a distal endportion; a sensor system comprising: an electrically active sensorpositioned to sense a characteristic of an environment in which thedistal end portion of the shaft is located, a data transmission lineelectrically coupled to the electrically active sensor and extendingalong the shaft, the data transmission line configured to transmit datasignals to and from the electrically active sensor, and a powertransmission line electrically coupled to the electrically active sensorand extending along the shaft, the power transmission line configured totransmit power to the electrically active sensor; and a floating groundelement electrically coupled with the sensor system, wherein voltageinduced by an electromagnetic interference external to the endoscopicsystem in at least one of the data transmission line and the powertransmission line is substantially similar to the voltage induced by theelectromagnetic interference on the floating ground element.
 16. Theendoscopic system of claim 15, wherein the floating ground element isoperably coupled to provide an electrical reference for the sensorsystem.
 17. The endoscopic system of claim 15, further comprising anelectrically insulative material separating the floating ground elementfrom each of the data transmission line and the power transmission line.18. The endoscopic system of claim 15, further comprising an opticaltransceiver operably coupled to the data transmission line.
 19. Theendoscopic system of claim 15, further comprising a power regulatorelectrically coupled to the power transmission line and to the floatingground element, the power regulator configured to convertground-referenced power received from an earth ground referenced powersource into floating ground element referenced power and to output thefloating ground element referenced power through the power transmissionline.
 20. The endoscopic system of claim 15, wherein the floating groundelement comprises a conductive structure at least partially surroundingone or both of the data transmission line and the power transmissionline.